Their fullbacks are often used like TE’s and visa versa in their offense. Short passes go to them and it allows them to have the outlet pass, when the coverage is too good downfield to pass deep. It can also give them a player to worry the defense a little more as they can use short crossing patterns out of the backfield, that will occupy the linebackers on defense. It is just a little twist to add variety to the pro style offense. They have some big kids there, so they can plow for some of the tough yardage as well.